000
FXUS64 KJAN 032035
AFDJAN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
335 PM CDT FRI SEP 3 2010

...COOL EARLY FALL AIRMASS EXPECTED THIS HOLIDAY WEEKEND...

.DISCUSSION...SFC FRONT IS SLOWLY PUSHING SE AND IS LOCATED ACROSS
THE NW PORTION OF THE CWA AS OF 3 PM. SFC CONVERGENCE PEAKED ALONG
AND AHEAD OF THE FRONT BETWEEN NOON AND 2 PM...BUT NOW THE BOUNDARY
IS MOVING INTO MORE VEERED SFC WINDS AND THE LOW LEVEL CONVERGENCE
IS BECOMING LESS PRONOUNCED. HOWEVER...SFC HEATING HAS PEAKED AND
THERE ARE SOME OUTFLOW BOUNDARIES PROPAGATING E/SE AND THOSE ARE
AIDING IS LOW LEVEL CONVERGENCE. THE END RESULT WILL BE ISOLATED
SHOWERS CONTINUING THROUGH 6-8 PM ALONG AND AHEAD OF THE SFC FRONT.
INSTABILITY REMAINS LIMITED...BUT THERE HAS BEEN ENOUGH TO SUPPORT
SOME VERY LIMITED THUNDER. THE HIGHEST INSTABILITY IS ACROSS THE SW
QUAD AND IT SHOULD REMAIN THAT WAY THROUGH THE REMAINDER OF THE
AFTERNOON.

THE MAIN FORECAST FOCUS IS THE EARLY FALL AIRMASS AND THE COOLISH
TEMPS EXPECTED THROUGH MON. AS OF 3 PM...THE SFC FRONT WAS LOCATED
GENERALLY FROM SHV TO TUP. BY 10 PM...PORT GIBSON TO JAN TO
DEKALB...AND BY 4 AM...MOVING THROUGH THE PINE BELT. MUCH DRIER AIR
WILL FILTER IN BEHIND THE FRONT AND THIS IS SUPPORTED BY AROUND 50
DEGREE DEWPTS ACROSS MOST OF AR. ADDITIONALLY...COOLER LOW LEVEL
TEMPS WILL MOVE IN AS WELL WITH READINGS ROUGHLY 1 TO 1.5 STANDARD
DEV BELOW THE NORM BASED OFF FORECAST VALUES. A SIMILAR ANALOG FOR
THIS EVENT WAS BACK IN EARLY SEPT 1952. THIS EVENT SET SEVERAL
RECORD LOWS FOR 2-3 DAYS. OUR CURRENT SETUP FOR THE WEEKEND HAS MANY
SIMILARITIES TO 1952...BUT IT IS NOT AS COOL. NONETHELESS...IT WILL
BE QUITE COOL FOR EARLY SEP WITH A RECORD OR TWO IN JEOPARDY SUN
MORNING. OVERALL...LOOK FOR LOWS IN THE 50S TO LOWER 60S THROUGH
MON. HIGHS WILL RANGE FROM THE LOWER/UPPER 80S SAT...WITH MORE 85-90
SUN. OVERALL...TEMPS WILL BE SOME 5-8 DEGREES BELOW SEASONAL
AVERAGES FOR THE WEEKEND. ENJOY /CME/

PREV LONG TERM...GLOBAL MODELS ARE IN GENERAL AGREEMENT ON THE
UPCOMING WEATHER PATTERN FOR THE ARKLAMISS NEXT WEEK. IT WILL BE
MAINLY DRY EAST...BUT THE CHANCE FOR WETTER WEATHER WILL INCREASE
OVER WESTERN PORTIONS OF THE ARKLAMISS...ESPECIALLY FOR TUESDAY AND
BEYOND. SEASONABLE TEMPERATURES ARE EXPECTED...AND NO TROPICAL
SYSTEMS ARE FORECAST TO AFFECT THE AREA NEXT WEEK.

A MODERATELY STRONG SUBTROPICAL HIGH IS FORECAST TO MAINTAIN DRY
WEATHER AS IT BUILDS QUICKLY OVER THE LOWER MS VALLEY REGION FROM
SUNDAY INTO LABOR DAY. A RATHER COOL START TO SUNDAY MORNING IS
EXPECTED WITH TEMPERATURES DIPPING INTO THE MID AND UPPER 50S OVER
MOST OF THE AREA. THE LAST TIME IT DIPPED BELOW 60 DEG F AT THE
JACKSON INTL AIRPORT WAS MAY 10TH...SO A LITTLE CHILL IN THE AIR
SHOULD CERTAINLY BE FELT SUNDAY MORNING.

THE SUBTROPICAL HIGH WILL SHIFT EASTWARD ENOUGH BY TUESDAY TO ALLOW
DEEP LAYER RETURN FLOW TO DEVELOP...ESPECIALLY FOR THE AREA WEST OF
THE I-55 CORRIDOR WHERE THE GFS INDICATES THAT PRECIPITABLE WATER
WILL INCREASE TO AROUND TWO INCHES...AND HAVE ACCEPTED THE LOW-END
CHANCE POPS FROM GFS MOS. MODELS ALSO INDICATE THERE WILL BE ENOUGH
INSTABILITY FOR GETTING A FEW AFTERNOON AND EVENING THUNDERSTORMS
EACH DAY. OTHERWISE...LOOK FOR DAYTIME TEMPERATURES TO BE A FEW
DEGREES HOTTER THAN CLIMATIC AVERAGE WITH THE MEAN POSITION OF THE
SUBTROPICAL RIDGE SETTING UP OVER THE SOUTHEAST CONUS. /EC/

.AVIATION...GENERALLY VFR CONDITIONS WILL PREVAIL ACROSS THE REGION
THROUGH SATURDAY AFTERNOON. A COLD FRONT...MOVING SOUTHWARD ACROSS
THE REGION...WILL HAVE MOVED SOUTH OF THE AREA BY THIS EVENING.
NORTHERLY WINDS AT 7 TO 12 KT WILL CONTINUE IN THE WAKE OF THE FRONT
THROUGH LATE THIS AFTERNOON...WITH THE STRONGEST WINDS ACROSS THE
NORTHWEST DELTA REGION. NORTH WINDS WILL DECREASE BELOW 5 KT
TONIGHT...BEFORE INCREASING TO 5 TO 10 KT ON SATURDAY. ISOLATED
SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE PASSAGE OF THE FRONT
MAINLY THROUGH 04/0000 UTC. AREAS AROUND KJAN WILL HAVE THE GREATEST
CHANCE OF EXPERIENCING THIS ACTIVITY THROUGH 03/2100 UTC. MVFR TO
IFR CEILINGS/VISIBILITIES ARE EXPECTED WITH THIS ACTIVITY...ALONG
WITH WIND GUSTS TO 25 KT. HOWEVER...THE CHANCE FOR SHOWERS/STORMS
IMPACTING ANY GIVEN TAF SITE IS TOO LOW FOR MENTION IN THE TAFS AT
THIS TIME. /COHEN/

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       62  86  57  89 /  12   0   0   0
MERIDIAN      61  86  52  89 /  12   0   0   0
VICKSBURG     59  86  54  89 /  12   0   0   0
HATTIESBURG   67  91  59  92 /  20   1   1   4
NATCHEZ       62  84  57  88 /  20   0   0   1
GREENVILLE    57  83  54  88 /   0   0   0   0
GREENWOOD     55  83  53  88 /   2   0   0   0

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.

CME/COHEN/EC